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From: Isaku Yamahata <isaku.yamahata@gmail.com>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>
Cc: Isaku Yamahata <isaku.yamahata@intel.com>,
	cohuck@redhat.com, ehabkost@redhat.com, kvm@vger.kernel.org,
	mst@redhat.com, seanjc@google.com, alistair@alistair23.me,
	xiaoyao.li@intel.com, qemu-devel@nongnu.org, mtosatti@redhat.com,
	pbonzini@redhat.com, isaku.yamahata@gmail.com
Subject: Re: [RFC PATCH 02/23] kvm: Switch KVM_CAP_READONLY_MEM to a per-VM ioctl()
Date: Mon, 22 Feb 2021 19:23:01 -0800	[thread overview]
Message-ID: <20210223032301.GA88084@private.email.ne.jp> (raw)
In-Reply-To: <0f29a789-9822-3dd8-b827-e5b86b933059@redhat.com>

On Tue, Feb 16, 2021 at 08:56:45AM +0100,
Philippe Mathieu-Daudé <philmd@redhat.com> wrote:

> Hi Isaku,
> 
> On 2/16/21 3:12 AM, Isaku Yamahata wrote:
> > Switch to making a VM ioctl() call for KVM_CAP_READONLY_MEM, which may
> > be conditional on VM type in recent versions of KVM, e.g. when TDX is
> > supported.
> > 
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> > ---
> >  accel/kvm/kvm-all.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> > index 47516913b7..351c25a5cb 100644
> > --- a/accel/kvm/kvm-all.c
> > +++ b/accel/kvm/kvm-all.c
> > @@ -2164,7 +2164,7 @@ static int kvm_init(MachineState *ms)
> >      }
> >  
> >      kvm_readonly_mem_allowed =
> > -        (kvm_check_extension(s, KVM_CAP_READONLY_MEM) > 0);
> > +        (kvm_vm_check_extension(s, KVM_CAP_READONLY_MEM) > 0);
> 
> Can this check with "recent KVM" be a problem with older ones?
> 
> Maybe for backward compatibility we need:
> 
>           = (kvm_vm_check_extension(s, KVM_CAP_READONLY_MEM) > 0) ||
>             (kvm_check_extension(s, KVM_CAP_READONLY_MEM) > 0);

Agreed. That's safer and it's difficult to check the very old version of kenel
and non-x86 arch.

Thanks,

-- 
Isaku Yamahata <isaku.yamahata@gmail.com>


  reply	other threads:[~2021-02-23  3:23 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-16  2:12 [RFC PATCH 00/23] [RFC PATCH 00/24] TDX support Isaku Yamahata
2021-02-16  2:12 ` [RFC PATCH 01/23] target/i386: Expose x86_cpu_get_supported_feature_word() for TDX Isaku Yamahata
2021-02-16  7:53   ` Philippe Mathieu-Daudé
2021-02-16  2:12 ` [RFC PATCH 02/23] kvm: Switch KVM_CAP_READONLY_MEM to a per-VM ioctl() Isaku Yamahata
2021-02-16  7:56   ` Philippe Mathieu-Daudé
2021-02-23  3:23     ` Isaku Yamahata [this message]
2021-02-16  2:12 ` [RFC PATCH 03/23] KVM: i386: use VM capability check for KVM_CAP_X86_SMM Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 04/23] i386/kvm: Move architectural CPUID leaf generation to separarte helper Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 05/23] vl: Introduce machine_init_done_late notifier Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 06/23] hw/i386: Introduce kvm-type for TDX guest Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 07/23] i386/kvm: Squash getting/putting guest state for TDX VMs Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 08/23] i386/kvm: Skip KVM_X86_SETUP_MCE for TDX guests Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 09/23] target/i386: kvm: don't synchronize guest tsc for TD guest Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 10/23] linux-headers: Update headers to pull in TDX API changes Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 11/23] hw/i386: Initialize TDX via KVM ioctl() when kvm_type is TDX Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 12/23] target/i386/tdx: Finalize the TD's measurement when machine is done Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 13/23] i386/tdx: Frame in tdx_get_supported_cpuid with KVM_TDX_CAPABILITIES Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 14/23] i386/tdx: Frame in the call for KVM_TDX_INIT_VCPU Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 15/23] i386/tdx: Add hook to require generic device loader Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 16/23] hw/i386: Add definitions from UEFI spec for volumes, resources, etc Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 17/23] i386/tdx: Add definitions for TDVF metadata Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 18/23] i386/tdx: Parse tdvf metadata and store the result into TdxGuest Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 19/23] i386/tdx: Create the TD HOB list upon machine init done Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 20/23] i386/tdx: Add TDVF memory via INIT_MEM_REGION Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 21/23] i386/tdx: Use KVM_TDX_INIT_VCPU to pass HOB to TDVF Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 22/23] i386/tdx: Force x2apic mode and routing for TDs Isaku Yamahata
2021-02-16  2:13 ` [RFC PATCH 23/23] target/i386: Add machine option to disable PIC/8259 Isaku Yamahata

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